Heating unit for cooking

ABSTRACT

A fuel burning unit for cooking food in which a variable air supply is combined with a variable fuel supply mechanism to provide a uniform stable flame in which gas consumption is held to an efficient minimum. The air supply is varied by changing the size of an air admitting opening which is on the exterior portion of the fuel burning unit. The air opening is varied in size by reciprocal movement of a handle located on the fuel burning unit whereby desired amounts of air can be admitted into the unit to be mixed with a desired amount of fuel which can be ignited to produce a stable flame.

United States Patent [72] inventor Everett L. Kimball 2,825,325 3/1958 Ross 431/344X Stroudsburg, Pa. 3,001,573 9/ 1961 Hunter et a1 43 l/344X [21] App]. No. 835,531 3,360,967 1/1968 Massie 431/344X [22] Filed June 23, 1969 Prima 13/ Exammer-Carroll B. Dority, Jr. [45] Patented Apr. 13, 1971 [73] Assignee Ronson Corporation Attorney Marvm Tnmas Woodbridge, NJ.

[54] HEATING UNIT FOR COOKING 6 Clams 1 Dmwmg ABSTRACT: A fuel burning unit for cooking food in which a U-S. Variable air upply is combined a variable fuel upply 239/414,431/354 mechanism to provide a uniform stable flame in which gas [51 hit. F23d consumption is to an efficient minimum, The air upply is [50] Field of Search 431/344, a i d b hanging th size of an air admitting opening which 354; 126/38, 44; 239/414; 137/607 is on the exterior portion of the fuel burning unit. The air opening is varied in size by reciprocal movement of a handle [56] References C'ted located on the fuel burning unit whereby desired amounts of UNITED STATES PATENTS air can be admitted into the unit to be mixed with a desired 1,178,509 4/1916 Fowler 137/607 amount of fuel which can be ignited to produce a stable flame.

HEATING UNIT FOR COOKING BACKGROUND OF THE INVENTION Portable cooking units for use both indoors and outdoors are known. These devices have become very successful in the market because of their great versatility. These portable cookers made it possible to bring the flame to the place where the cooking is to be done instead of having to take the food where the source of heat is.

One of the drawbacks of the prior art cooking devices, however, is their inability to maintain a stable flame. The flame on these devices sputters at low flame setting and they are difficult to control on a high flame setting. The reason the gas sputters is that too much primary air in the mixture blows the gas out of the burner orifices too quickly. The result is the gas momentarily goes out and is then ignited again. Gas consumption is also much higher when the flame is intermittent.

Since the burners in the portable cooking units generally have a fixed primary air opening the mixture is usually too lean at a low flame setting and too rich at a high flame setting.

SUMMARY OF THE INVENTION It is an object of this invention to provide an aspirator which will vary the amount of primary air which is mixed with fuel. The beneficial results from the latter is the production of a stable flame and a more economical utilization of fuel.

In the embodiment shown a fuel reservoir serves as the base for a burner through which an air gas mixture escapes to be ignited. The gas mixture is regulated by means of a valve located in the handle of the device. A needle valve controls the flow of liquefied gas and a variable air opening controls the amount of primary air which is mixed with the gas. By rotating a knob on the handle of the device, a needle valve opens and closes an aperture which meters the fuel to the burner. Simultaneously therewith, an opening permitting the entry of air is varied in size to provide the precise ratio of liquefied gas to air to obtain the most efficient fuel mixture for burning. The escaping gas is then ignited and the flame height adjusted by rotating a knob on the handle.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a cross section of the flame burning mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, there is shown the preferred embodiment of my invention comprising a base consisting of a circular or other shape casting formed of an upstanding circular wall 11 and a bottom wall 12. An inlet valve I3, which can be of the type depicted in US. Pat. No. 3,085,601 filed Aug. 3 l, 1960 and issued on Apr. 16, 1963 to Conrad Zellweger, is screwed into the bottom wall 12 of the base. The inlet valve forms a convenient mechanism for replenishing the fuel in the base.

A cover 14 rests upon and closes the open end of the base 10. The cover 14 has a peripheral ridge I5 thereon which sits on the wall 11, and a depending skirt 16 which extends into the fuel reservoir. Integral with the cover 14 is an extension housing 17 having a longitudinal bore 18 therein. The bore I8 narrows into an intermediate bore 19 which intersects with a cross bore 20. The cross bore leads into outlet bore 21 which leads to the atmosphere. The extension housing 17 has a threaded opening 22 therein which will be further described below. The cover 14 terminates in a socket 23 for the reception of the burner subassembly. I I A bushing 24 is secured within the extension housing I7. The bushing has openings 25 therein which function to admit gas to the venturi nozzle 26 in the end of the bushing. The opposite end of the bushing 24 has screw threads 27 tapped therein, into which is threaded an elongated adjusting shaft 28.

The shaft 28 has mounted thereon a tapered adjusting needle29 which is loosely held in a retaining member 30 which is integral with the shaft 28. The needle is loosely held on the shaft so that it can precisely center itself in the venturi nozzle 26 thereby avoiding the expense of maintaining close tolerances at the venturi section. Adjacent the retaining member 30 is a threaded section 31 which is threaded into the corresponding female threads 27 in the bushing 24. Thus, by rotating the shaft 28 it can be inserted into or withdrawn from the bushing 24. The adjusting needle 29 is thereby inserted or withdrawn from the venturi nozzle 26 which varies the size of the venturi opening thereby adjusting the gas flow. Adjacent the threaded portion 31 is an enlarged barrel 32 which is integral with the shaft 28 or the shaft can be glued or otherwise fixed to the barrel. The barrel has a groove 33 therein into which is placed an O-ring 33. The O-ring functions to prevent gas from leaking through the rear of the device by passing through the extension housing 17. A knob 34 which can be serrated to provide a gripping surface thereon is secured to the end of the shaft 28 and by rotating the knob, the shaft will be correspondingly rotated.

A handle housing 35 is movably mounted on the extension I7 and its hollow bore 36 encompasses the shaft 28. A rib 37 or a plurality of ribs can be integral with the handle housing 35 such that longitudinal movement of the shaft 28 will be transmitted to the handle housing. This occurs when the barrel 32 moves to the right as shown in FIG. I and abuts against the rib 37. Longitudinal movement of the handle is limited by the size of the opening 38 bored in the lower end of the handle 35. A screw 39, or any other known stop member, which is screwed into the tapped opening 22 in the extension 17, serves to limit the movement of the handle 35 such that the latter can only be moved a desired distance.

The forward end 40 of the handle 35 abuts against a decorative strip 41 which surrounds the base 10 and against a top plate 42 when the valve is in the closed position; however, it will be noted that as the handle is moved to the right relative to the base 10, an air opening 43 appears and the size of the opening will vary according to the distance the handle 35 is moved from the base 10.

The burner subassembly comprises a reflector 44 having a skirt 45 thereon which fits into a ceramic insulator 46. The insulator prevents heat from passing down into the fuel reservoir 10.

Gas is fed into the venturi opening 26 at the upstream or right-hand end of the venturi. The gas, which can be a liquefied petroleum gas such as butane, travels through a tube 55 in the fuel reservoir through the openings 25 in the bushing 24 through the hollow bushing to the venturi orifice 26 into the axial bore or mixing chamber 20 thence to the atmosphere.

The primary air enters the unit at the opening 43 formed between the handle 35 and the base 10. The air then travels between the space 56 formed by the cover 42 and the longitudinal extension 17 into the mixing chamber 20 where it combines with the gas and exits through the burner openings 57 to the atmosphere whereupon the combined air-gas mixture is ignited.

The ceramic insulator can be pressed into the socket 23 in the base 10 where it can also serve to clamp atinnerman nut 47 in place. A second insulator 48 having a bore 29 therein and a socket 50 is supported within the opening in the reflector 44 on an inwardly turned flange 51 on the reflector. The burner head 52 has an opening 53 therein for the reception of a screw 54 or other clamping member. The screw 54 is threaded into the tinnerman nut 47 and thereby maintains the burner, the reflector and the insulators on the base 10.

In actual operation, theknob 34 is rotated in a counterclockwise direction. Since the knob is fixed to the shaft 28, the shaft also rotates. The shaft is threaded into the bushing 24 and the shaft thereby moves to the right when it is unscrewed. Since the needle is attaeh'ed to the shaft, it too moves to the right thereby opening the venturi orifice 26. The barrel 32 fixed to the shaft 28 moves to the right and strikes the rib 37 secured to the handle 35 thereby forcing the handle to the right also. The left shoulder of the opening 38 will strike the fixed abutment 39 thereby limiting further movement of the handle 35.

As the handle gradually moves to the right an opening 43 is formed between the handle 35 and the base which permits primary air to enter .the device which mixes with the fuel passing through the variable venturi orifice 26. The air-fuel mixture combine in the mixing chamber and exit through openings in the burner head where the mixture is ignited to provide a stable flame.

While there has been shown and described a single embodiment of the invention, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention, and that it is intended by the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

lclaim:

l. A fuel burning mechanism for producing a variable flame which comprises:

a. a base having an upstanding wall which surrounds and closes a reservoir for fuel;

b. a burner head mounted on the fuel reservoir having a fuel passageway extending between the burner head and the fuel reservoir whereby fuel can be transferred to the burner head;

0. fuel metering means mounted in the fuel passageway for varying the supply of fuel transferred to the burner head; and

d. a variable air supply means on the fuel reservoir responsive to graduated movement of the fuel metering means for mixing a predetermined volume of air with a predetermined quantity of fuel in which the variable air supply means comprises a movable member on the fuel reservoir, the movable member varies the size of an air aperture leading to the fuel passageway.

2. A fuel burning mechanism as defined in claim 1 in which the fuel metering means comprises a tapered needle valve adapted to vary the flow path through an orifice in the fuel passageway.

3. A fuel burning mechanism as defined in claim 1 in which an elongated handle is attached to the fuel reservoir and is operatively connected to the needle valve such that movement of the handle serves to vary the size of the orifice in which the needle valve is located.

4. A fuel burning mechanism as defined in claim 1 in which the air aperture is formed between the fuel reservoir and the movable member such that movement of the movable member toward and away from the reservoir varies the size of the air aperture to respectively close and open the air aperture.

5. A fuel burning mechanism as defined in claim 1 which comprises:

a. a base having an upstanding wall which surrounds and closes a reservoir for fuel;

b. a burner head mounted on the fuel reservoir having a fuel passageway extending between the burner head and the fuel reservoir whereby fuel can be transferred to the burner head;

c. fuel metering means mounted in the fuel passageway for varying the supply of fuel transferred to the burner head;

d. a variable air supply means on the fuel reservoir responsive to graduated movement of the fuel metering means for mixing a predetermined volume of air with a predetermined quantity of fuel, including;

e. a handle having a bore longitudinally extending therethrough;

f. a shaft reciprocally mounted within the bore; and

g. the variable air supply means comprising the handle having means thereon responsive to movement of the shaft to vary the size of an air opening leading to the fuel P3553 6. A fue burning mechanism as defined in claim 5 in which UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 1571 505 Dated A ril 13. 1971 lnventor(s) Everett L. Kimball It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the specification, column 2, line 63, numeral "29" should be --49-- In the claims, claim 5 should be an independent claim, therefore, the words in the preamble "as defined in claim 1" should be cancelled.

Signed and sealed this 7th day of September 1971.

(SEAL) Attest:

fi g z g ggfifig: ROBERT GOTTS CHALK Acting Commissioner of Pater 

1. A fuel burning mechanism for producing a variable flame which comprises: a. a base having an upstanding wall which surrounds and closes a reservoir for fuel; b. a burner head mounted on the fuel reservoir having a fuel passageway extending between the burner head and the fuel reservoir whereby fuel can be transferred to the burner head; c. fuel metering means mounted in the fuel passageway for varying the supply of fuel transferred to the burner head; and d. a variable air supply means on the fuel reservoir responsive to graduated movement of the fuel metering means for mixing a predetermined volume of air with a predetermined quantity of fuel in which the variable air supply means comprises a movable member on the fuel reservoir, the movable member varies the size of an air aperture leading to the fuel passageway.
 2. A fuel burning mechanism as defined in claim 1 in which the fuel metering means comprises a tapered needle valve adapted to vary the flow path through an orifice in the fuel passageway.
 3. A fuel burning mechanism as defined in claim 1 in which an elongated handle is attached to the fuel reservoir and is operatively connected to the needle valve such that movement of the handle serves to vary the size of the orifice in which the needle valve is located.
 4. A fuel burning mechanism as defined in claim 1 in which the air aperture is formed between the fuel reservoir and the movable member such that movement of the movable member toward and away from the reservoir varies the size of the air aperture to respectively close and open the air aperture.
 5. A fuel burning mechanism as defined in claim 1 which comprises: a. a base having an upstanding wall which surrounds and closes a reservoir for fuel; b. a burner head mounted on the fuel reservoir having a fuel passageway extending between the burner head and the fuel reservoir whereby fuel can be transferred tO the burner head; c. fuel metering means mounted in the fuel passageway for varying the supply of fuel transferred to the burner head; d. a variable air supply means on the fuel reservoir responsive to graduated movement of the fuel metering means for mixing a predetermined volume of air with a predetermined quantity of fuel, including; e. a handle having a bore longitudinally extending therethrough; f. a shaft reciprocally mounted within the bore; and g. the variable air supply means comprising the handle having means thereon responsive to movement of the shaft to vary the size of an air opening leading to the fuel passageway.
 6. A fuel burning mechanism as defined in claim 5 in which stop means is formed on the handle to limit reciprocal movement of the handle with respect to the fuel reservoir. 